SCHEMA

- Client

- Invoker

- Receiver

- ICommand

- ConcreteCommand

• Client
  - creates a ConcreteCommand object and sets its receiver
  - act as a Controller and ask Invoker to fulfill the request
   
• Invoker
  - Holds commands and "asks" it to carry out the request
   
• Receiver 
  - knows how to perform the operations associated with carrying out the request.
   
• ICommand
  - declares an interface for executing an operation
   
• ConcreteCommand
  - defines a binding between a Receiver object and an action
  - implements Execute by invoking the corresponding operation(s) on Receiver

Invoker (CommandCollector)

ConnectToOracleServerCommand (IServerCommand)

ServerProxy (Receiver)

- checkNetwork
- createConnection
- storeConnection
- informClientWithStatus

.execute()

ApplicationProxy (Receiver)

- getAccessToken
- getCachedData
- updateConnectionType
- doSomethingOnThread

SaveImageContentCommand (IContentCommand)

private Object State

GUI

GUI

GUI

GUI

View

IDEA

- Encapsulate processing to an Object 

- Easy functionality replacement

- Combining actions

- State holder

- Delay calls
 

A command
is a extracted
method call.

It’s a method call wrapped in an object.

an object  that you can stick in a variable, pass to a function, etc.

closure
callback
function pointer

first-class function

partially applied function

Direct execution 
to hide unnecessary code.

Command can return value, 
even Promise.

github

- be stored with key for later use (Observer)
- execute another commands (Macros)
- do business logic and act as a brain
- hold and modify state or data
- be sequenced (Async)

Commands

can

I SEE FIRE

Benefits

- Loose coupling
- No duplication
- Reusable code
- Better Tests

EXAMPLES

COMMAN

Global object that act as Callback holder and Invoker, 
but return Promise

https://github.com/DQvsRA/JavaScript-Meteor-CMS

https://github.com/DQvsRA/Java-Test-PureMVC-Example

PureMVC

by Mr. Cliff Hall

puremvc.org